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Metamath Proof Explorer

Theorem nfel2

Description: Hypothesis builder for elementhood, special case. (Contributed by Mario Carneiro, 10-Oct-2016)

Ref Expression
Hypothesis nfeq2.1 ⊢ Ⅎ _ x B
Assertion nfel2 ⊢ Ⅎ x A ∈ B

Proof

Step Hyp Ref Expression
1 nfeq2.1 ⊢ Ⅎ _ x B
2 nfcv ⊢ Ⅎ _ x A
3 2 1 nfel ⊢ Ⅎ x A ∈ B